A cluster switching system (CSS, Cluster Switch System), also referred to as a stack, means that multiple switches are combined together and virtualized into one switching device. When a stack is set up, switches that form the stack send a stack contention packet to each other, to elect an active switch according to a preset rule, and the active switch is used to manage the cluster switch system.
After the active switch is determined, only the active switch can register with a controller. The active switch sends a registration request to the controller, and the active switch and the controller interact with each other after a channel is established.
However, in the prior art, after an active switch is elected, the active switch does not change, and only the active switch can register with a controller. If the registration of the active switch fails, the active switch continuously initiates new registration. When the active switch does not change, a result is still a registration failure. As a result, a stack device is in a hosted state for a long time until intervention of operation and maintenance personnel.